394 THE PHOSPHORUS CONTENT OF THE 



unable to reduce materially the amount of ash by any process 

 of purification. 



Since these experiments, the study of the so-called dyspep- 

 tone has been resumed by various investigators. Thus, Szon- 

 tagh * similarly prepared a dyspeptone which he found to 

 contain organic phosphorus to the extent of 2.96-3.53 per 

 cent an amount somewhat less than that observed by Lu- 

 bavin. Again, results of analyses by C. Willdenow f show a 

 phosphorus content (3.85 per cent) agreeing more closely 

 with the figures of Lubavin. 



Salkowski,}: in a later communication, pointed out that the 

 amount of dyspeptone, henceforth called paranuclein in accord 

 with the more recent nomenclature, varies according to the 

 conditions of proteolysis. After a vigorous digestion as little 

 as 6.7 per cent of the original casein remained undissolved as 

 paranuclein, while under less favorable conditions the separa- 

 tion of paranuclein took place to the extent of even 20 per 

 cent Still more recently Salkowski has observed that 

 where the proteolysis is carried out under extremely favorable 

 conditions, the separation of paranuclein may be wanting en- 

 tirely. In the former cases, however, the phosphorus content 

 of the paranuclein varied from 2.11 to 2.41 per cent the 

 higher content coming from products resulting from the more 

 favorable conditions. Salkowski has found the phosphorus 

 just described to exist in organic combination, and has shown 

 that as much as fifteen per cent of the original phosphorus of 

 the casein may be retained in the paranuclein formed from it. 



From analyses of paranuclein (pseudonuclein) made by 

 Sebelien || this author finds a phosphorus content varying from 

 2.5 to 2.76 per cent. He attributes the lack of agreement in 



* Szontagh, Jahresbericht f iir Thierchemie, 1892, xxii, p. 170. 



t Willdenow, Inaugural-Dissertation, Bern, 1893 (Drechsel's laboratory). 



J Salkowski and Hahn, Archiv fiir die gesammte Physiologic, 1894, lix, 

 p. 225. 



Salkowski, Centralblatt fiir die medicinische Wissenschaften, 1893, xxxi, 

 p. 385. Cf . also Alexander, Zeitschrif t fiir physiologische Chemie, 1898, xxv, 

 p. 425. 



y Sebelien, Zeitschrif t fiir physiologische Chemie, 1895, xz, p. 446. 



